A magnetooptic disk in which a medium surface is heated by using a laser beam and the direction of magnetization is changed by applying a magnetic field to the surface, thereby recording digital data has been put into practical use.
In recent years, a request for a magnetooptic disk of a low cost in which digital data of a larger capacity can be recorded has been rising. To satisfy such a request, there have been proposed magnetooptic disks of an MSR (Magnetically induced Super Resolution) system such as a DWDD (Domain Wall Displacement Detection) system having a multilayer film structure in which a plurality of magnetic layers have been laminated and the like. Those magnetooptic disks have an advantage such that, in principle, linear recording density can be much increased without being limited by a wavelength of the laser beam or a Numerical Aperture (NA) of an objective lens.
As a manufacturing method of those magnetooptic disks, a manufacturing method of sequentially laminating a plurality of magnetic layers onto one principal plane of a substrate by using a single wafer type sputtering apparatus has been examined.
However, the manufacturing method of laminating the magnetic layers onto one principal plane of the substrate by using the single wafer type sputtering apparatus has a problem such that since the number of sputtering processing vessels increases, manufacturing facilities become complicated and increase in size.
There is also a problem such that the increase in number of sputtering processing vessels causes an increase in manufacturing costs and a tact time of the magnetooptic disks.
If the number of magnetic layers is decreased to solve those problems, deterioration of signal characteristics is caused. It is because, in the magnetooptic disks of the MSR system such as a magnetically amplified detection system or the like, it is indispensable to increase the number of magnetic layers in order to realize the high-quality signal characteristics of high-density recording and reproduction which are independent of an optical system.